In a bizarre way (please don't take this as US bashing or global empiricism), I think one of the main reasons the US will never accept it as a sport is that it's a game that the US can be beaten at, and quite convincingly by nations that are 30 times smaller in population than they are (Czech Republic). In sporting terms this does not and will never compute with the average American.
In regards to the officiating, it's actually been quite refreshing in comparison to some recent World Cups - I can understand that diving and faking can seem overplayed in replays, especially in slow motion - but the decisions made in the US v Italy game were in line with the new FIFA guidelines, the Mastroeni tackle could well have broken the opposing player's leg and I can quite understand the ref's decision.
When the only padding the players wear are shin protectors (shin pads) I think the officials should always err on the side of caution and penalise harshly those that are at fault, my personal opinion.